1. Field of the Invention
The present invention generally relates to the field of manufacture and assembly of circuit boards. More specifically, the present invention relates to a method of transferring component tape information to a component mounting machine, a tape guide for guiding a component tape in a component mounting machine, and a tape magazine for receiving the tape guide.
2. Description of Background Art
Generally, within the field of manufacture and assembly of circuit boards, electronic components are fed to a component mounting machine for mechanically and/or electrically mounting the components onto a circuit board. These surface mounted components are often delivered spaced apart along the length of a component tape, which consists of a lower carrier tape provided with compartments, one for each component, and an upper cover, or cover tape or protective tape. After positioning the electronic components in the corresponding compartments, the cover tape is attached to the carrier tape, and the component tape is wound on a component reel. The attachment of the cover tape to the carrier tape can, for instance, be performed by providing either the cover tape or the carrier tape with adhesive areas, or by fusing the cover tape to the carrier tape. Then, the component reel is transferred to a component mounting machine, which is provided with feeding mechanisms for feeding a component to a certain predetermined picking position where it can be picked, or collected, by a pick-up head. Alternatively, the component reel can be transferred to a component tape magazine, which in turn is inserted into the component mounting machine. Then, it is generally the magazine that is equipped with the feeding mechanisms for performing the described feeding of the component tape. WO 86/00778 shows a cassette magazine for a component mounting machine using the above described method.
Generally, a circuit board is provided with a wide variety of different components, and a component mounting machine can be used for the manufacturing of a variety of different circuit boards. Therefore, a substantial number of different types of components are provided to a component mounting machine, wherein each type of component is contained on a separate component tape. The component mounting machine, or the process controlling the machine, must therefore know exactly which type of component can be found at which picking position in the machine. Traditionally, following the loading of a component tape into a component mounting machine or a tape magazine, this is performed by manually entering the position and the type of component of each component tape into memory means used by the machine. This time consuming process must be performed each time a new component tape is loaded into the machine.
Furthermore, when entering the position and component type manually, there is always a considerable risk of entering the wrong type of component or the wrong position. This would inevitably lead to circuit boards being erroneously mounted, or lead to a halt in the manufacturing process until the error has been corrected. In recent years, the use of bar codes has simplified the above-described process. When the component tape has been loaded into its position in a component mounting machine, the position and the type of components are entered by reading both a bar code provided at each tape position in the machine, and a bar code provided on the component tape reel. Still, this process has to be repeated each time a new component tape is entered into the machine, and the risk of reading the bar code for an adjacent, incorrect position in the machine is still there, even though the use of bar codes reduces the risk involved with the above-described process.
When using a tape magazine, a component tape reel is loaded at each of a number of different positions in the magazine. Information regarding the position of the tape reel and the type of components contained on the reel is entered into the machine for each position, along with the magazine identity. Thereby, when switching between two magazines, entering the identity of the new magazine can be sufficient, provided that the positions and type of components of the component tapes have not changed since the magazine were last used. Any change would again require the entering of at least the position and the component type.
It is also preferred if the component mounting machine have knowledge of have many components there are left on the tape in order to optimise the mounting process, and to alert in time that a component tape is about to run out of its components. This information can also be entered manually upon loading a new tape into the machine. Then, the machine could count the number of components that have been picked from the tape and, thereby, derive the number of remaining components on the tape. However, if the component tape is removed from the machine, e.g. when replaced by a type of component needed for a particular circuit board, this information is lost.
According to the method conventionally used within the art, the loading of a component tape in a component mounting machine involves the following steps. Placing the component tape reel into the tape holder of a component mounting machine, or into a tape magazine of a component mounting machine; introducing the free end of the component tape into a feeding mechanism, provided in the machine or in the magazine, such that feeding pins engage corresponding holes provided in the component tape; separating, by hand, the end of the cover tape from the end of the carrier tape for a distance sufficient for the cover tape to be engaged with a cover tape handling means; and lowering a locking mechanism over the carrier tape for holding the carrier tape against the feeding mechanism.
As realised from the above, the loading of a component tape in a component mounting machine and the related entering of component information is a time-consuming process that has to be performed every time a new component has to be added to the circuit board manufacturing process, and every time an empty component tape has to be replaced. The process is also connected with a certain element of risk regarding errors in relation to the more or less manual entering of information. This negatively affects the overall time efficiency of the manufacturing process and, hence, the overall costs.